镁合金的等离子体电解氧化工艺优化及膜的耐腐蚀性

为优化AZ31镁合金的等离子体电解氧化工艺,并对制得的陶瓷膜的耐腐蚀性能进行电化学动力学研究.利用四因素(Na_2SiO_3浓度、KOH浓度、电解氧化电压和电解氧化时间)、三水平的田口方法优化工艺条件,并采用动电位极化曲线扫描评价AZ31镁合金等离子体电解氧化陶瓷膜的耐腐蚀性能.结果表明:该陶瓷膜的耐腐蚀性能受田口正交矩阵中各水平的影响显著,KOH质量浓度对耐腐蚀性能的影响最大;耐腐蚀性能的最优实验参数为:Na_2SiO_3质量浓度20g/L,KOH质量浓度4g/L,电解氧化电压300V和电解氧化时间40min.

Optimization of Plasma Electrolytic Oxidation Process and Corrosion Resistance of Oxide Coatings

In order to optimize the plasma electrolytic oxidation (PEO) process of AZ31 magnesium alloy and investigate the corrosion resistance of the prepared ceramic coatings in terms of electrochemical kinetics, the Taguchi method was used to perform an orthogonal test in terms of four factors (namely, Na_2SiO_3 concentration, KOH concentration, electrolytic oxidation voltage and time) and three levels, and the corrosion resistance of the PEO cera-mic coatings was evaluated by scanning the potentiodynamic polarization curve. It is found that the three levels in the Taguchi orthogonal array all significantly influence the corrosion resistance, and KOH mass concentration is a major affecting factor;and that, when the PEO is performed with 20g/L Na_2SiO_3 and 4g/L KOH at 300V for 40min, the ceramic coatings are of the highest corrosion resistance.